JP2008300387A - Etching gas flow controller and control method of local dry etching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an etching gas flow controller of a local dry etching device according to capable of facilitating the setting of optimum overhang amounts and clearance amounts corresponding to roll-off shapes different at each semiconductor wafer, capable of controlling an etching amount according to the shape of a semiconductor wafer outer peripheral part, and achieving improvement in the flatness of a semiconductor wafer outer peripheral edge such as roll-off and an SFQR. <P>SOLUTION: The etching gas flow controller is equipped with: a plate type mask body M which can cut a portion of a flow of etching gas jetted from a nozzle of the local dry etching device toward a semiconductor wafer W at the edge of the mask body M on the forward side of the gas flow, and is formed of a material having resistance against exposure to the gas; and a sending device which moves the plate type mask body M as local etching progresses. The sending device can adjust a position of the edge of the plate type mask body M according to an edge roll-off shape of the semiconductor wafer, so that it need not be replaced at each edge roll-off shape. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for improving edge roll-off and reducing edge exclusion in numerically controlled dry etching processing of a semiconductor wafer, and further relates to an etching gas flow control apparatus and method for a local dry etching apparatus.

  Conventionally, a local dry etching method is known as one processing method for flattening the surface of a semiconductor wafer. In the local dry etching method, the activated species gas generated by plasma is ejected from the nozzle, and the ejected activated species gas is sprayed on the surface of the semiconductor wafer. Since silicon or the like reacts with the active species gas and is removed as a gaseous compound, the surface material of the semiconductor wafer is thinned.

  At this time, when the nozzle is relatively moved along the surface of the semiconductor wafer, the amount of thinning removed from the surface can be controlled according to the speed. The relative movement is usually performed by scanning, a scanning pitch corresponding to the surface irregularities of the semiconductor wafer obtained in advance is determined, and the surface of the semiconductor wafer is planarized by controlling the scanning speed.

  Therefore, such an apparatus is called a local dry etching apparatus, and the relative movement is usually controlled by an attached numerical control apparatus. The local dry etcher simply exposes the entire surface to the plasma (and thus controls to obtain a different thickness for each part) in that the controlled relative motion results in a different thickness for each part of the surface. It is different from the dry etching apparatus as the surface treatment apparatus.

  The semiconductor wafer is a substantially disk-shaped plate body, and a bevel surface is formed on the front and back of the entire circumference of the semiconductor wafer, and a part of a flat surface inside the bevel surface is a wiring pattern forming surface. FIG. 1 is a partial enlarged cross-sectional view around a semiconductor wafer, showing the vicinity of the boundary between the flat surface and the bevel surface. Edge roll-off means that, as shown by A, in the vicinity of the boundary portion between the flat surface P for forming the wiring pattern and the bevel surface B, the height of the flat surface P is lower than the original and falls like a shoulder. Say that you are. Edge roll-off A often occurs in a polishing process prior to a local dry etching process.

  The local dry etching apparatus is provided with information including edge roll-off A information along with unevenness on the center side of the flat portion of each semiconductor wafer, and local dry etching is performed based on this information. Since the change in thickness is steep, the difference in scanning speed between this part and the inner part thereof becomes very large. Note that the unevenness removed by local dry etching is at the nanometer level, and the above “steepness” means that it is steep when viewed at the nanometer level.

  FIG. 2 is a graph showing changes in the machining allowance a necessary for eliminating (flattening) the edge roll-off portion and changes in the machining allowance b that can be actually handled by the apparatus. As shown in this figure, it is impossible to reduce the thickness of the edge roll-off A as in the case of the required change in the machining allowance a. It cannot be removed. Note that the bevel surface B itself is not included in the target of local dry etching.

  In recent years, in order to improve the yield of semiconductors, it is desired to form as many wiring patterns as possible on the flat portion P. However, the edge roll-off A is subjected to local dry etching processing to eliminate this as described above. Therefore, the area where the wiring pattern cannot be formed, that is, the edge exclusion E cannot be reduced.

  Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-349687) discloses a technique for solving such a problem. In a local plasma etching apparatus, an outer peripheral mask having a flange covering the outer peripheral edge of a semiconductor wafer is disclosed. By reducing the exposure of the plasma treatment to the outer peripheral edge of the semiconductor wafer, the sagging of the outer peripheral edge represented by edge roll-off of the semiconductor wafer is improved, and the overhang amount of the flange with respect to the semiconductor wafer, It is shown that the etching amount of the outer peripheral edge can be controlled by the clearance between the flange and the semiconductor wafer, and that the improvement of SFQR (Site Front least sQuares Range) and the improvement of the yield due to the reduction of edge exclusion can be obtained. ing.

  The roll-off shape of the edge is formed by the previous process for manufacturing a semiconductor wafer, and has a similar shape depending on the process. Therefore, the standard roll is used for the overhang amount and clearance amount of the flange portion of the outer peripheral mask. Actually, the amount corresponding to the off-shape is set from data obtained by experiments or the like.

  FIG. 3 shows an example of the peripheral mask in the prior art. The outer peripheral mask has a ring shape and is fixed with the semiconductor wafer W inside. An inner flange 614 overhanging inward suppresses plasma exposure to the edge roll-off. The amount of exposure (and hence the gradual thickness suppression amount) depends on the overhang amount of the inner flange and the distance from the surface of the semiconductor wafer (clearance amount).

  FIG. 4 is a graph showing the relationship between the overhang amount and the removal rate (etching) suppression rate, and FIG. 5 is a graph showing the relationship between the clearance amount and the removal rate. As can be seen from these graphs, the gradual wall thickness suppression rate varies depending on the overhang amount d and the clearance amount h of the inner flange 614 of the outer peripheral mask. Since the amount of overhang is easier to control the etching amount than the amount of clearance, the clearance amount is usually fixed, and the roll-off of the edge is controlled mainly by changing the overhang amount.

  Regarding the overhang amount and the clearance amount, as described in the specification of the above-mentioned publication, even a slight change of about 0.1 mm greatly changes the roll-off shape created by processing. Therefore, high precision is required for the dimensions of the outer peripheral mask and the mounting position on the semiconductor wafer. Furthermore, the peripheral mask, particularly its flange portion, is difficult to process because it is necessary to use a material that is sufficiently resistant to plasma exposure. For this reason, peripheral masks of various dimensions are prepared in advance, and the peripheral mask most suitable for the semiconductor wafer of the lot is selected and used according to the semiconductor wafer diameter, roll-off shape, etc. ing.

  In recent years, requirements for roll-off, SFQR, etc. have become more stringent for semiconductor wafers, and finer precision is also required for the shape and flatness of the outer peripheral edge, such as edge roll-off in the above-mentioned local plasma etching. Is now required. As a result, it has become difficult to meet this requirement by selecting an outer peripheral mask for each lot of semiconductor wafers as described above, for the following reason.

  Local dry etching is performed in a vacuum chamber. A certain amount of time is required to evacuate the chamber. For this reason, from the viewpoint of efficiency, after a plurality of semiconductor wafers are previously stored in a vacuum chamber in units of lots, the chamber is evacuated, and the semiconductor wafers are sequentially transferred onto a processing table and processed.

  If it is intended to cope with different edge roll-offs for each semiconductor wafer, not only a large number of lots of semiconductor wafers but also a large number of peripheral masks must be accommodated in the vacuum chamber. Furthermore, a mask exchange device that can exchange the outer peripheral mask and fix it with high accuracy is also required. Time is also required to replace the peripheral mask. Since the vacuum chamber must be evacuated, it is more efficient to reduce its volume as much as possible. From this point of view, it is not reasonable to accommodate a large number of replacement outer peripheral masks and mask changers in the vacuum chamber. Furthermore, the setup for changing the outer peripheral mask for each semiconductor wafer requires a very long time, and thus cannot be adopted at all.

  Further, when the shape of the outer peripheral edge portion such as the roll-off of the edge for each semiconductor wafer is different also in the direction (orientation) along the outer periphery, the fixed outer peripheral mask as described above responds to this difference. It is not possible to obtain the optimum overhang amount and clearance amount.

The prior art documents considered to be related to the present invention are listed below.
Japanese Patent Application Laid-Open No. 2004-349587 JP 2004-241466 A Japanese Patent Laid-Open No. 7-183280 JP 2001-308077 A JP 2004-165645 A JP 2001-1444076 A JP 2002-176030 A Journal of the Japan Society for Abrasive Technology Vol.44 No.10 2000 OCT. P.437-440

  In view of the above problems, the problem to be solved by the present invention is that the optimum overhang amount and clearance amount corresponding to different roll-off shapes for each semiconductor wafer can be easily set, and the shape of the outer peripheral edge of the semiconductor wafer It is an object to provide an etching gas flow control device for a local dry etching apparatus that can control the etching amount in accordance with the above and can improve the flatness of the outer peripheral edge of the semiconductor wafer such as roll-off and SFQR.

  The above problem is solved by the following means. That is, according to the first invention, in the flow of the etching gas ejected from the nozzle of the local dry etching apparatus toward the semiconductor wafer, it is possible to block a part of the gas flow at the edge, and the gas exposure. Etching gas for a local dry etching apparatus, comprising: a plate-like mask body made of a material resistant to the above, and a feeding device for moving the plate-like mask body according to the progress of local etching Flow control device.

  According to a second invention, in the etching gas flow control device of the local dry etching apparatus of the first invention, the plate-like mask body forms an annular body having a circular hole inside, and the plate-like mask. A feed device for moving the body includes a first frame that moves straight up and down with respect to the wafer table of the local dry etching device, a second frame that moves straight in a direction perpendicular to the straight movement direction of the first frame, and the second frame A third frame that moves in a direction orthogonal to both the linear movement direction of the two frames and the linear movement direction of the first frame, and the first, second, and third frames, respectively, for driving An etching gas flow control device for a local dry etching device, comprising first, second and third driving devices.

  According to a third aspect of the invention, in the etching gas flow control device of the local dry etching apparatus of the first aspect, the plate-like mask body has a fan shape that is a part of an annular body having a circular hole inside. The feeding device for moving the plate-shaped mask body is a first frame that moves straight up and down with respect to the wafer table of the local dry etching device, and the linear movement direction of the first frame on the first frame. A second frame that rotates about an axis that faces, a third frame that moves linearly toward the axis of the second frame on the second frame, the first frame, the second frame, and the second frame An etching gas flow control device for a local dry etching apparatus comprising first, second and third driving devices for driving three frames, respectively. It is.

  According to a fourth aspect of the present invention, in the etching gas flow control device of the local dry etching apparatus of the first aspect, the plate-like mask body has a fan shape that is a part of an annular body having a circular hole inside. The feeding device for moving the plate-shaped mask body is a first frame that moves straight up and down with respect to the wafer table of the local dry etching apparatus, and an axis that passes through the center of the wafer table on the first frame. The second frame that rotates around, the first frame, and the first and second driving devices for driving the second frame, respectively, and the circular hole of the plate-like mask body. The center is an etching gas flow control device of a local dry etching device, wherein the etching gas flow control device is arranged off the center of the wafer table.

  According to a fifth aspect of the present invention, in a flow of etching gas ejected from a nozzle of a local dry etching apparatus toward a semiconductor wafer, a part of the gas flow is exposed to gas according to the shape of the outer peripheral edge of the semiconductor wafer. An etching gas flow control method for a local dry etching apparatus characterized in that the edge of a plate-shaped mask body made of a material having resistance to shielding is blocked and the plate-shaped mask body is moved in accordance with the progress of local etching. .

  According to the present invention, it becomes possible to adjust the overhang amount and clearance amount of the plate-shaped mask body with respect to the peripheral edge of the semiconductor wafer according to the shape of each semiconductor wafer, and precisely control the removal amount of the outer periphery during etching. It is possible to improve the quality of semiconductor wafers such as roll-off and SFQR.

  In the etching gas flow control device of the local dry etching apparatus according to the present invention, a part of the gas flow is provided at the edge portion in front of the flow of the etching gas ejected from the nozzle of the local dry etching device toward the semiconductor wafer W. And a feeding device for moving the plate-like mask body M according to the progress of local etching. It has been.

  The position of the edge of the plate-shaped mask body M can be adjusted by this feeding device according to the edge roll-off shape of the semiconductor wafer, so that it is not necessary to replace every edge roll-off shape as in the conventional outer peripheral mask. The above-mentioned problems in the prior art can be solved. In the following, two embodiments of the present invention will be described with reference to the drawings. However, the local dry etching apparatus itself is the same as the conventional one and is well known as disclosed in the above-mentioned patent documents and the like. Is omitted.

  FIGS. 6 and 7 are a schematic plan view and a partial front view (sectional view) of the etching gas flow control device 1 of the local dry etching device, respectively, and show an example belonging to the first embodiment. The plate-like mask body M1 of this embodiment is plate-like and has an annular shape having a circular hole E1 inside.

  The feeding device for moving the plate-like mask body M1 includes a first frame Fz that moves straight up and down with respect to a wafer table T that is an electrostatic chuck of a local dry etching device, and a linear movement direction of the first frame Fz. A second frame Fy that moves straight in a right angle direction, and a third frame Fx that moves straight in a direction orthogonal to both the straight movement direction of the second frame Fy and the straight movement direction of the first frame Fz are provided. Furthermore, a first drive device Dz (not shown), a second drive device Dy, and a third drive device Dx for driving the first frame Fz, the second frame Fy, and the third frame Fx, respectively, are provided. Yes.

  The first driving device Dz (not shown), the second driving device Dy, and the third driving device Dx are, for example, a feed screw Sz (not shown), Sy, Sx, a stepping motor, a servo motor, and the like for controlling them. Motor Mz (not shown), My, and Mx. Each motor is controlled by a controller (not shown).

  The center of the annular plate-like mask body M1 can control the relative position with respect to the semiconductor wafer by the driving device. When moving in the x and y directions, the position in the z-axis direction does not change. By controlling the position in the z-axis direction, the amount of clearance between the plate mask body M1 and the semiconductor wafer can be arbitrarily set. Can be set.

  The etching gas flow control device 1 is fixed on a wafer table T of a local dry etching device, that is, an XY stage (not shown) that can move in the XY direction of the local dry etching device. The XY stage moves relative to the fixed nozzle N, whereby the etching gas ejected from the nozzle N toward the semiconductor wafer W scans the semiconductor wafer W.

  In Example 1, a prescribed plate mask body M1 having an inner edge E1 having an inner diameter corresponding to the edge roll-off shape of a standard semiconductor wafer is prepared as the plate mask body M1. That is, as shown in FIG. 8, the prescribed plate-like mask body M1 to be prepared has an inner diameter that is too large by δ1 (that is, overhanging) with respect to a semiconductor wafer whose edge roll-off extends from the standard to the inside. On the other hand, the inner diameter is too small by δ2 (that is, the overhang amount is too large) for a semiconductor wafer having a smaller edge roll-off than the standard one.

  At the time of processing, numerical control data such as moving speed of stage scanning is calculated based on the shape of the semiconductor wafer measured in advance, and at the same time, the clearance amount and overhang amount suitable for this are also determined by the roll-off shape data of the semiconductor wafer. Calculated. The clearance amount is set by moving by the servo mechanism in the z-axis direction described above.

  If the calculated overhang amount is the same as the prescribed overhang amount, the center of the plate-like mask body M1 is set to be concentric with the center of the semiconductor wafer, and scanning is performed in this state. Needless to say, the overhang is the specified amount at this time.

  A case where the calculated overhang amount is larger than the prescribed overhang amount by δ1 will be described with reference to FIGS. In an actual local dry etching apparatus, the nozzle N is fixed and the semiconductor wafer W, the wafer table T, and the plate-like mask body M1 move. However, in order to make the explanation easy to understand, the following figure is based on the semiconductor wafer W. Show.

  In the scanning, the nozzle N fixes the X position on the semiconductor wafer W, changes the position in the Y direction, scans one line, then changes the X position, changes the direction in the Y direction, and returns to one line. It is assumed that the scanning is moved over the entire surface of the semiconductor wafer by repeating the scanning of the minute.

  A scanning line in the Y direction will be described as an example. A line connecting the nozzle N and the center of the semiconductor wafer W when the nozzle N is at the position shown in FIG. 9 (XY coordinates (x1, y1), circumferential direction θ1). The position of the plate-like mask body M1 relative to the semiconductor wafer is moved so that the center of the plate-like mask body M1 comes to a position away from the center of the semiconductor wafer by δ1 in the direction opposite to the nozzle N. As a result, as shown in the drawing, the overhang amount of the plate-like mask body M1 in the vicinity of the nozzle N is increased by δ1.

  When the scanning is at the position of FIG. 10 (XY coordinates (x2, y2), circumferential direction θ2), and when the scanning is at the position of FIG. 11 (XY coordinates (x3, y3), circumferential direction θ3), each figure is shown. By moving the plate-like mask body M1 so as to have the same relationship as described above in accordance with the scanning of the nozzle N, the overhang amount can always be increased by δ1 from the standard near the nozzle N.

  A case where the calculated overhang amount is smaller than the prescribed overhang amount by δ2 will be described with reference to FIGS. In this case, when the scanning of the nozzle N is at the position of FIG. 12 (XY coordinates (x1, y1), circumferential direction θ1), the semiconductor wafer W in the direction of the nozzle N on the line connecting the nozzle N and the semiconductor wafer W center. The plate-shaped mask body M1 is moved with respect to the semiconductor wafer W so that the center of the plate-shaped mask body M1 comes to a position away from the center by δ2.

  When the scanning is at the position of FIG. 13 (XY coordinates (x2, y2), circumferential direction θ2) and when the scanning is at the position of FIG. 14 (XY coordinates (x3, y3), circumferential direction θ3), FIG. As a result, as shown in the figure, the overhang amount of the plate-like mask body M1 near the nozzle N is smaller than the standard by δ2.

  For example, when the semiconductor wafer W is transferred to the wafer table T by the transfer robot, the center position of the placed semiconductor wafer W may vary depending on the positioning accuracy of the transfer robot. Even in such a case, the position of the placed semiconductor wafer W is measured each time, and this position information is sent to the peripheral mask positioning device (overhang amount control means), and the position of the plate-like mask body M1 with respect thereto By correcting this, it becomes possible to correct the error of the semiconductor wafer transfer position.

  FIG. 15 shows a data processing flow of the local plasma etching processing including the above processing. First, in S01, the surface shape of a semiconductor wafer to be processed is measured in advance by a shape measuring instrument which is a semiconductor wafer shape measuring means. The shape data to be measured is 5 mm from the outer periphery of the semiconductor wafer, such as roll-off shape, in addition to the surface normal or back surface reference (normal) semiconductor wafer surface shape data excluding edge exclusion (edge exclusion region). Shape data about the outer periphery up to the inside is included.

  In S02, the normal semiconductor wafer surface shape data output from the shape measuring instrument is input to the arithmetic unit, where the position and speed data corresponding to the shape (scanning pitch and scanning speed of the XY stage on which the semiconductor wafer is placed). Is converted to The data here is grid data corresponding to XY coordinates, and is output to an X-axis motor control device (not shown) and a Y-axis motor control device (not shown), which are XY stage control means.

  Thus, the XY stage on which the semiconductor wafer is placed is scanned with respect to the plasma source with its position and speed controlled, and the semiconductor wafer shape is flattened by controlling the etching amount of the semiconductor wafer. At this time, since the outer peripheral edge of the semiconductor wafer has a sagging shape compared to other portions, there is almost no removal amount by etching, and therefore, as described above, in addition to the removal amount control by speed data. It is necessary to control the etching suppression amount by the overhang amount and clearance amount of the plate-like mask body M1.

  In S03, the shape data for the outer peripheral edge that is the basis for calculation such as roll-off is also input to the arithmetic unit, and here, the removal suppression amount for the outer peripheral edge is calculated. The removal suppression amount data here is in a polar coordinate format corresponding to the overhang and clearance control means, and the overhang amount and clearance amount are obtained as follows based on the removal suppression amount data.

  Here, the relationship between the overhang amount and the removal suppression rate is obtained by experiments in advance for various cases in which the clearance amount is changed. Here, the removal suppression rate is a ratio of the etching removal amount at a place where there is no influence of the cover by the plate-like mask. For example, the influence of the etching gas blown onto the semiconductor wafer is exerted at a constant nozzle speed. This is calculated based on the difference in removal amount for each grid position on the semiconductor wafer when the entire range is scanned. The relationship between the overhang amount, the clearance amount, and the removal suppression rate obtained in this way is stored in a storage unit of the arithmetic device as a referenceable form such as a table or a database.

  In S04, with respect to this removal suppression rate converted into polar coordinates represented by r-θ, the distribution of the removal suppression rate in the radial direction r at the θ position for each appropriately divided circumferential position is an overrun obtained in advance by experiments. Compared with the distribution shape of the relationship between the hang amount, clearance amount and removal suppression rate, the overhang amount and clearance amount for the most suitable distribution shape are extracted.

  The extracted overhang amount and clearance amount are data given to the first drive device Dz, the second drive device Dy, and the third drive device Dx of the feeding device that is the overhang and clearance control means of the etching gas flow control device 1. Is output as This data corresponds to the position of the XY stage for scanning. In other words, the control of the XY stage is adjusted so as to have a speed corresponding to the scanning position of the XY stage with respect to the nozzle N. At this time, the polar coordinates corresponding to the position of the XY stage are synchronized with the control of the XY stage. This is data of the overhang amount and clearance amount corresponding to the θ position.

  That is, in FIGS. 9 and 12, when the XY stage is at (x1, y1), the overhang amount and the clearance amount correspond to the position of θ1, and in FIGS. 10 and 13, when it is at (x2, y2). In FIG. 11, FIG. 11 and FIG. 14, when it is at (x3, y3), it corresponds to θ3.

  The scanning data for the XY stage obtained as described above and the data for the etching gas flow control feeding device are output, and the local dry etching device and the etching gas flow control device are controlled.

  When the scanning movement of the XY stage is at a stage position where the influence of the nozzle N does not reach the outer peripheral edge portion, the overhang and clearance control of the plate-like mask body M1 may not be performed, but the control is usually performed. In order to make it easy, overhang and clearance control are performed at the θ position corresponding to this position. By doing so, for example, in the overhang and clearance control on the Y-axis line where the nozzle N passes through the center of the XY stage, it is possible to avoid sudden fluctuations in the control amount.

  By performing the control described above, the position of the plate-like mask body M1 is corrected even when there is a positional non-uniformity in the sagging of the outer peripheral edge of the semiconductor wafer and the size is locally generated. The outer peripheral removal amount can be appropriately processed.

  FIGS. 16 and 17 are a schematic plan view and a partial front view (sectional view) of the etching gas flow control device 1 of the local dry etching device, respectively, and show an example belonging to the second embodiment. . The plate-like mask body M2 of this embodiment has a fan-shaped shape obtained by dividing the plate-like mask body M1 of the first embodiment in the circumferential direction, that is, a fan-like body that is a part of an annular body having a circular hole inside. . Further, the plate-like mask body M2 has a size capable of masking a range sufficiently larger than the range affected by the etching gas ejected from the nozzle during scanning.

  Further, the feeding device for moving the plate-like mask body M2 is a first frame Fz that moves straight up and down with respect to the wafer table T of the local dry etching device, and the straight movement of the first frame on the first frame. The second frame Fk that rotates around the direction of the axis, the third frame Fr that moves straight on the second frame Fk toward the rotation axis of the second frame Fk, the first frame Fz, and the second frame The first driving device Dz, the second driving device Dk, and the third driving device Dr (not shown) for driving Fk and the third frame Fr, respectively. That is, in addition to the shape of the plate-like mask body M2, the second embodiment is different from the first embodiment in that the second frame Fk and the second driving device Dk are rotary. The third frame Fr and the third drive device Dr correspond to the third frame Fx and the third drive device Dx of the first embodiment.

  The plate-like mask body M2 is coaxial with the semiconductor wafer W and the wafer table T, and includes a second frame Fk and a second driving device Dk as a circumferential movement mechanism that rotates and moves in the circumferential direction. Can be controlled. The third frame Fr and the third driving device Dr constitute a moving mechanism that moves the plate-like mask body M2 in the radial direction of the semiconductor wafer. Thereby, the amount of overhang is controlled. The second drive device Dk is specifically driven to be controllable by a motor Mk such as a servo motor or a stepping motor.

  As is clear from this, the overhang amount of the plate-like mask body M2 is controlled by the radial position and the circumferential angle. When the plate-like mask body M2 is moved in the radial direction and the circumferential direction, the position in the z-axis direction is not changed. As in the first embodiment, the movement in the z-axis direction is a servo motor. It is possible to set the clearance amount of the outer peripheral mask arbitrarily by using a mechanism capable of position control using.

  In machining, the clearance amount and the overhang amount are calculated as in the first embodiment. An example in the case of the plate-like mask body M2 set to a prescribed overhang amount is shown in FIG. Taking one line of scanning movement in the Y direction as an example, when the scanning is at the position shown in FIG. The angular position of the plate-like mask body M2 is adjusted by rotating the two frames Fk, and then the overhang amount is adjusted by moving the third frame Fr in the radial direction.

  By moving the plate-like mask body M2 in accordance with the scanning movement of the nozzle N so as to have the same relationship as described above, the outer periphery of the semiconductor wafer can be masked with a set overhang amount in the vicinity of the nozzle N. . Since the optimum overhang and clearance control of the outer peripheral mask can be performed according to the shape of the semiconductor wafer to be processed, the description is omitted because it is substantially the same as in the first embodiment.

  In the third embodiment, the etching gas flow control device can have a simpler structure by devising the shape of the plate-shaped mask body of the second embodiment. FIG. 19 is an explanatory diagram showing that the overhang amount of the plate-like mask body M3 can be adjusted by the plate-like mask body M3 of the present embodiment, the semiconductor wafer W, and the positional relationship between them.

  As in the second embodiment, the plate-like mask body M3 has a fan shape that is a part of an annular body having a circular hole inside. This plate-like mask body M3 is different from the second embodiment in that the center Ce of the circular hole is arranged away from the center Cw of the wafer table. By doing so, the inner edge E3 of the plate-like mask body M3 can intersect with the concentric circles of countless semiconductor wafers W virtually drawn. In other words, it indicates that when the amount of overhang is increased by, for example, δ1 from the specified overhang amount, the plate-like mask body M3 may be rotated around the center Cw in accordance with the position of the nozzle N.

  Since it is possible to rotate the plate-like mask body M3 around the center Cw by the second frame Fk, in the third embodiment, the third frame Fr and the third driving device Dr in the second embodiment are not necessary, and therefore In the etching gas flow control device 1 of the third embodiment, the structure is much simpler than that of the second embodiment.

  Heretofore, in the third embodiment, the inner edge E3 has been described as a part of a circle (arc). However, the curve forming the inner edge E3 is an infinite number of concentric circles of semiconductor wafers W drawn virtually. Obviously, the arcs are not necessarily arcs as long as they can be intersected with each other, and any one of them, for example, a parabola, a straight line, or another curve can be used without departing from the principle.

It is a partial expanded sectional view of the circumference | surroundings of a semiconductor wafer, Comprising: The boundary vicinity of a flat surface and a bevel surface is shown. It is a graph which shows the change of the allowance required in order to eliminate an edge roll-off part (flattening), and the change of the allowance which an apparatus can actually respond | correspond. It is an example of the outer periphery mask in a prior art. It is a graph showing the relationship between the amount of overhangs and the thinning (etching) suppression rate. It is a graph showing the relationship between a clearance amount and a thinning suppression rate. 1 is a schematic plan view of an etching gas flow control device 1 of a local dry etching device in Example 1. FIG. 1 is a schematic partial front view (sectional view) of an etching gas flow control device 1 of a local dry etching device in Example 1. FIG. It is explanatory drawing which shows the regular plate-shaped mask body M1. It is explanatory drawing for demonstrating the relationship between the plate-shaped mask body M1 and a semiconductor wafer, when the calculated overhang amount is larger by δ1 than the prescribed overhang amount. It is explanatory drawing for demonstrating the relationship between the plate-shaped mask body M1 and a semiconductor wafer, when the calculated overhang amount is larger by δ1 than the prescribed overhang amount. It is explanatory drawing for demonstrating the relationship between the plate-shaped mask body M1 and a semiconductor wafer, when the calculated overhang amount is larger by δ1 than the prescribed overhang amount. It is explanatory drawing for demonstrating the relationship between the plate-shaped mask body M1 and a semiconductor wafer, when the calculated overhang amount is smaller by δ2 than the prescribed overhang amount. It is explanatory drawing for demonstrating the relationship between the plate-shaped mask body M1 and a semiconductor wafer, when the calculated overhang amount is smaller by δ2 than the prescribed overhang amount. It is explanatory drawing for demonstrating the relationship between the plate-shaped mask body M1 and a semiconductor wafer, when the calculated overhang amount is smaller by δ2 than the prescribed overhang amount. The flow of data processing of local plasma etching processing is shown. 6 is a schematic plan view of an etching gas flow control device 1 of a local dry etching device in Example 2. FIG. It is a typical partial front view (sectional view) of the etching gas flow control apparatus 1 of the local dry etching apparatus in Example 2. It is explanatory drawing which shows the relationship between the plate-shaped mask body M2 in Example 2, and the amount of overhangs. It is explanatory drawing which shows that the overhang amount of the plate-shaped mask body M3 can be adjusted with the plate-shaped mask body M3 of Example 3, the semiconductor wafer W, and the positional relationship of both.

Explanation of symbols

1 Etching gas flow control device 614 Inner flange A Edge roll-off B Bevel surface Dz, Dy, Dx, Dk Driving device E Edge exclusion E1, E3 Edge Fk Frame (Rotating)
Fz, Fy, Fx, Fr Frame (going straight)
M, M1, M2, M3 Plate mask body Mx, My, Mz, Mk, Mr Motor N Nozzle P Flat part, flat surface Sx, Sy, Sz Feed screw T Wafer table W Semiconductor wafer a, b Tolerance d Overhang amount h Clearance amount

Claims (5)

In the flow of etching gas ejected from the nozzle of the local dry etching apparatus toward the semiconductor wafer, a part of the gas flow can be blocked at the edge, and the material is resistant to gas exposure. A plate-shaped mask body, and
An etching gas flow control device for a local dry etching apparatus, comprising a feeding device for moving the plate-like mask body in accordance with the progress of local etching. In the etching gas flow control device of the local dry etching device according to claim 1,
The plate-shaped mask body has an annular body having a circular hole on the inside, and
The feeding device for moving the plate-shaped mask body is:
A first frame that moves straight up and down with respect to the wafer table of the local dry etching apparatus;
A second frame that moves linearly in a direction perpendicular to the linear movement direction of the first frame;
A third frame that moves linearly in a direction orthogonal to both the linear movement direction of the second frame and the linear movement direction of the first frame; and
An etching gas flow control device for a local dry etching apparatus, comprising first, second, and third driving devices for driving the first, second, and third frames, respectively. In the etching gas flow control device of the local dry etching device according to claim 1,
The plate-shaped mask body has a fan shape that is a part of an annular body having a circular hole inside, and
The feeding device for moving the plate-shaped mask body is:
A first frame that moves straight up and down with respect to the wafer table of the local dry etching apparatus;
A second frame which rotates on the first frame about an axis which faces the linear movement direction of the first frame;
A third frame that moves straight toward the axis of the second frame on the second frame; and
An etching gas flow control device for a local dry etching apparatus, comprising first, second, and third driving devices for driving the first frame, the second frame, and the third frame, respectively. In the etching gas flow control device of the local dry etching device according to claim 1,
The plate-shaped mask body has a fan shape that is a part of an annular body having a circular hole inside, and
The feeding device for moving the plate-shaped mask body is:
A first frame that moves straight up and down with respect to the wafer table of the local dry etching apparatus;
A second frame rotating on an axis passing through the center of the wafer table on the first frame; and
The first and second driving devices for driving the first frame and the second frame, respectively,
An etching gas flow control device for a local dry etching apparatus, wherein the center of the circular hole of the plate-shaped mask body is arranged away from the center of the wafer table. In the flow of the etching gas ejected from the nozzle of the local dry etching apparatus toward the semiconductor wafer, a part of the gas flow is made from a material resistant to gas exposure according to the shape of the outer peripheral edge of the semiconductor wafer. An etching gas flow control method for a local dry etching apparatus, wherein the plate mask body is shielded by an edge of the plate mask body and the plate mask body is moved in accordance with the progress of local etching.

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